On 16 October 2015 at 18:58, Fabio Estevam <feste...@gmail.com> wrote:
> From: Fabio Estevam <fabio.este...@freescale.com>
>
> Add the SPI NOR protection mechanism from the kernel.
>
> This code is based on the work from Brian Norris <computersforpe...@gmail.com>
>
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/mtd/spi-nor/spi-nor.c?id=62593cf40b23b523b9fc9334ca61ba6c595ebb09
>
> Signed-off-by: Fabio Estevam <fabio.este...@freescale.com>
> ---
> Changes since v6:
> -Point the original patch location from the kernel
>
> drivers/mtd/spi/sf_ops.c | 189
> +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 189 insertions(+)
>
> diff --git a/drivers/mtd/spi/sf_ops.c b/drivers/mtd/spi/sf_ops.c
> index 900ec1f..059cdd3 100644
> --- a/drivers/mtd/spi/sf_ops.c
> +++ b/drivers/mtd/spi/sf_ops.c
> @@ -15,6 +15,7 @@
> #include <spi_flash.h>
> #include <watchdog.h>
> #include <linux/compiler.h>
> +#include <linux/log2.h>
>
> #include "sf_internal.h"
>
> @@ -573,3 +574,191 @@ int sst_write_bp(struct spi_flash *flash, u32 offset,
> size_t len,
> return ret;
> }
> #endif
> +
> +#ifdef CONFIG_SPI_FLASH_STMICRO
> +#define SR_BP0 BIT(2) /* Block protect 0 */
> +#define SR_BP1 BIT(3) /* Block protect 1 */
> +#define SR_BP2 BIT(4) /* Block protect 2 */
Move these macros to header.
> +
> +static void stm_get_locked_range(struct spi_flash *nor, u8 sr, loff_t *ofs,
Already point this "*nor' notation in previous versions, please use flash.
And also don't post next level patches until the current version
discussion on ends.
> + u32 *len)
> +{
> + u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> + int shift = ffs(mask) - 1;
> + int pow;
> +
> + if (!(sr & mask)) {
> + /* No protection */
> + *ofs = 0;
> + *len = 0;
> + } else {
> + pow = ((sr & mask) ^ mask) >> shift;
> + *len = nor->size >> pow;
> + *ofs = nor->size - *len;
> + }
> +}
> +
> +/*
> + * Return 1 if the entire region is locked, 0 otherwise
> + */
> +static int stm_is_locked_sr(struct spi_flash *nor, loff_t ofs, u32 len,
> + u8 sr)
> +{
> + loff_t lock_offs;
> + u32 lock_len;
> +
> + stm_get_locked_range(nor, sr, &lock_offs, &lock_len);
> +
> + return (ofs + len <= lock_offs + lock_len) && (ofs >= lock_offs);
> +}
> +
> +/*
> + * Check if a region of the flash is (completely) locked. See stm_lock() for
> + * more info.
> + *
> + * Returns 1 if entire region is locked, 0 if any portion is unlocked, and
> + * negative on errors.
> + */
> +int stm_is_locked(struct spi_flash *nor, loff_t ofs, u32 len)
> +{
> + int status;
> + u8 sr;
> +
> + status = spi_flash_cmd_read_status(nor, &sr);
> + if (status < 0)
> + return status;
> +
> + return stm_is_locked_sr(nor, ofs, len, sr);
> +}
> +
> +/*
> + * Lock a region of the flash. Compatible with ST Micro and similar flash.
> + * Supports only the block protection bits BP{0,1,2} in the status register
> + * (SR). Does not support these features found in newer SR bitfields:
> + * - TB: top/bottom protect - only handle TB=0 (top protect)
> + * - SEC: sector/block protect - only handle SEC=0 (block protect)
> + * - CMP: complement protect - only support CMP=0 (range is not
> complemented)
> + *
> + * Sample table portion for 8MB flash (Winbond w25q64fw):
> + *
> + * SEC | TB | BP2 | BP1 | BP0 | Prot Length | Protected Portion
> + *
> --------------------------------------------------------------------------
> + * X | X | 0 | 0 | 0 | NONE | NONE
> + * 0 | 0 | 0 | 0 | 1 | 128 KB | Upper 1/64
> + * 0 | 0 | 0 | 1 | 0 | 256 KB | Upper 1/32
> + * 0 | 0 | 0 | 1 | 1 | 512 KB | Upper 1/16
> + * 0 | 0 | 1 | 0 | 0 | 1 MB | Upper 1/8
> + * 0 | 0 | 1 | 0 | 1 | 2 MB | Upper 1/4
> + * 0 | 0 | 1 | 1 | 0 | 4 MB | Upper 1/2
> + * X | X | 1 | 1 | 1 | 8 MB | ALL
> + *
> + * Returns negative on errors, 0 on success.
> + */
> +int stm_lock(struct spi_flash *nor, u32 ofs, u32 len)
> +{
> + u8 status_old, status_new;
> + u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> + u8 shift = ffs(mask) - 1, pow, val;
> +
> + spi_flash_cmd_read_status(nor, &status_old);
> +
> + /* SPI NOR always locks to the end */
> + if (ofs + len != nor->size) {
> + /* Does combined region extend to end? */
> + if (!stm_is_locked_sr(nor, ofs + len, nor->size - ofs - len,
> + status_old))
> + return -EINVAL;
> + len = nor->size - ofs;
> + }
> +
> + /*
> + * Need smallest pow such that:
> + *
> + * 1 / (2^pow) <= (len / size)
> + *
> + * so (assuming power-of-2 size) we do:
> + *
> + * pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
> + */
> + pow = ilog2(nor->size) - ilog2(len);
> + val = mask - (pow << shift);
> + if (val & ~mask)
> + return -EINVAL;
> +
> + /* Don't "lock" with no region! */
> + if (!(val & mask))
> + return -EINVAL;
> +
> + status_new = (status_old & ~mask) | val;
> +
> + /* Only modify protection if it will not unlock other areas */
> + if ((status_new & mask) <= (status_old & mask))
> + return -EINVAL;
> +
> + spi_flash_cmd_write_status(nor, status_new);
> +
> + return 0;
> +}
> +
> +/*
> + * Unlock a region of the flash. See stm_lock() for more info
> + *
> + * Returns negative on errors, 0 on success.
> + */
> +int stm_unlock(struct spi_flash *nor, u32 ofs, u32 len)
> +{
> + uint8_t status_old, status_new;
> + u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> + u8 shift = ffs(mask) - 1, pow, val;
> +
> + spi_flash_cmd_read_status(nor, &status_old);
> +
> + /* Cannot unlock; would unlock larger region than requested */
> + if (stm_is_locked_sr(nor, status_old, ofs - nor->erase_size,
> + nor->erase_size))
> + return -EINVAL;
> + /*
> + * Need largest pow such that:
> + *
> + * 1 / (2^pow) >= (len / size)
> + *
> + * so (assuming power-of-2 size) we do:
> + *
> + * pow = floor(log2(size / len)) = log2(size) - ceil(log2(len))
> + */
> + pow = ilog2(nor->size) - order_base_2(nor->size - (ofs + len));
> + if (ofs + len == nor->size) {
> + val = 0; /* fully unlocked */
> + } else {
> + val = mask - (pow << shift);
> + /* Some power-of-two sizes are not supported */
> + if (val & ~mask)
> + return -EINVAL;
> + }
> +
> + status_new = (status_old & ~mask) | val;
> +
> + /* Only modify protection if it will not lock other areas */
> + if ((status_new & mask) >= (status_old & mask))
> + return -EINVAL;
> +
> + spi_flash_cmd_write_status(nor, status_new);
> +
> + return 0;
> +}
Removed this else part based on the function_ptr checking in spi_flash.
> +#else
> +int stm_is_locked(struct spi_flash *nor, loff_t ofs, u32 len)
> +{
> + return 0;
> +}
> +
> +int stm_lock(struct spi_flash *nor, u32 ofs, u32 len)
> +{
> + return 0;
> +}
> +
> +int stm_unlock(struct spi_flash *nor, u32 ofs, u32 len)
> +{
> + return 0;
> +}
> +#endif /* CONFIG_SPI_FLASH_STMICRO */
> --
> 1.9.1
>
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thanks!
--
Jagan.
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